Trump administration policies — or the murkiness surrounding them — will increase millions of Americans’ health care premiums by double digits in 2018, a new nonpartisan study found.

In Wilmington, Del., for instance, consumers can expect a 49 percent hike on their rates.

President Donald Trump has sent mixed signals on how he plans to enforce the 2010 health care law, and the bill’s future in Congress, which has vowed to repeal and replace it, is uncertain.

The Kaiser Family Foundation’s analysis released Thursday said these circumstances have prompted insurers to charge higher premiums in 2018 than otherwise expected.

“Insurers attempting to price their plans and determine which states and counties they will service next year face a great deal of uncertainty,” the study said.

In the coming months, companies will ink contracts for their premiums in 2018, but Congress or the administration could make “significant changes…to the law — or its implementation” in the interim. And insurers could incur “significant losses” if they have not adequately priced in those charges.

Sen. Majority Leader Mitch McConnell and GOP leadership failed in their efforts to repeal Obamacare in July, and Republicans are now floating the possibility of working with Democrats to patch up the bill’s holes and stabilize the markets. Meanwhile, Trump hasn’t given up, and he’s been pressing Congress to do the same.

For a second day, Trump criticized McConnell, saying the majority leader “couldn't get it done.”

Can you believe that Mitch McConnell, who has screamed Repeal & Replace for 7 years, couldn't get it done. Must Repeal & Replace ObamaCare!

The key points vexing insurers is whether Congress will repeal the individual mandate, which compresses premiums by forcing healthy people to buy into coverage pools, or whether the administration will enforce the mandate.

They also don’t know if the administration will continue to subsidize them for implementing cost-sharing reductions, which are the subject of a lawsuit — or if Congress will buck up and appropriate these funds.

Millions of people’s costs for health coverage hinge on these decisions.

Researchers from Kaiser analyzed premiums for the second-lowest cost silver plan — a standard plan — in the major cities in 20 states and Washington, D.C.

Premiums will rise by at least 10 percent in 15 of those cities, the study found, though most consumers in the government-sponsored markets — about 10 million people in total — receive tax credits to help cover those increases.

But the 5 to 7 million Americans who buy individual policies on the open market, many of whom own small businesses, will have to scrabble enough money to pay full price.

Before his inauguration, Trump told the Washington Post that people covered under Obamacare “can expect to have great health care.” He said the health care policy in this country “will be in a much simplified form, much less expensive and much better.”

Yet Democratic legislators and governors from both parties have accused the president of destabilizing the markets.